Q3 of 23 Page 1

Attempt any three of the following sub questions:

Solve the following simultaneous equations by using Cramer’s rule:


3x - y = 7;


x + 4y = 11.

3x-y = 7 ………….(1)

X + 4y = 11


Multiplying both sides by 3


3(x + 4y) = 3×11


⇒ 3x + 12y = 33 ……………….(2)


Subtracting (2)-(1)


⇒ (3x + 12y)-(3x-y) = 33-7


⇒ 13y = 26


⇒ y = 2


Putting the value of y in (1)


3x-y = 7


⇒ 3x-(2) = 7


⇒ 3x = 9


⇒ x = 3.


The solution of equations is x = 3 and y = 2.


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